On a visit to Beijing, Zarif said he would also talk with Chinese officials about "bilateral ties and the very dangerous issues that are ongoing in our region today," according to a video published on the Iranian foreign ministry website.

Amid rising tensions in the Gulf, Iran on Thursday rejected negotiations with the US and said it was showing "maximum restraint" after Washington sent extra military forces to the region against what it claimed was an imminent threat from Tehran.

Zarif called on the international community to save the JCPOA, or Joint Comprehensive Plan of Action.

The landmark 2015 deal between Iran and world powers including the EU and the United States offered sanctions relief to Iran for scaling back its nuclear programme.

In May 2018 President Donald Trump withdrew the US from the deal and reinstated unilateral economic sanctions.

"If the international community and other JCPOA member countries and our friends in the JCPOA like China and Russia want to keep this achievement, it is required that they make sure the Iranian people enjoy the benefits of the JCPOA with concrete actions," Zarif said.

Zarif said last week that only Russia and China had supported Iran and helped it keep the nuclear deal going, and accused other parties to the agreement of letting Tehran down.

China was one of the eight global buyers -- India, Turkey, Japan, South Korea, Taiwan, Italy and Greece -- that was allowed to import Iranian crude oil before the US ended waivers in early May.

Zarif's China trip comes after visits to Turkmenistan, India and Japan in the past week.

Despite Washington's campaign of "maximum pressure" against Iran, the Islamic Republic has vowed to keep selling oil to its main customers, especially China, even if it takes using indirect means.

On May 8, Iranian President Hassan Rouhani said Iran would stop observing restrictions on stocks of enriched uranium and heavy water agreed under the nuclear deal in retaliation for the US withdrawal and the reimposition of sanctions.

In his announcement, Rouhani threatened to go further if the European members of the deal failed to start delivering on their promises to help Iran circumvent US sanctions within 60 days.

China in response called on all parties to uphold the nuclear deal in what it called a "shared responsibility".